Treated like a ******** for insuring with someone else

If They can not sell you insurance you will be treated like a ********!! Recieved a call offering me insurance from Standard Bank , initial interaction was very cheery and positive UNTIL I decline to insure with them. That is when this turned to the absalute worst. Firstly they demanded that I send them proof imediatly that my car is insured (Not older than 30 days and no copies) and if I do not do it imediatly I will be contacted by the legal department and" it will cost me dearly". I politely ended the call as my contract is with Vehicle and Asset Finance and they have proof of my insurance. This was Not the end as SB Motor Assist Insurance followed up with a very threatening email demanding My personal information and Proof of Insurance. My question here is are you so desperate to insure clients that you will resort to threaten those clients and treat them like ********* if they are insured somewhere else. This leaves a really bad taste in a long time SB customers mouth.